... Serial Interface 1 Port of DB9 Serial speed 75bps to 230Kbps Hardware RTS/CTS, software Xon/Xoff Signals: RS232: RS232: Rx, Tx, RTS ... , CTS, DTR, DSR, DCD, GND RS422: Rx+, Rx-, Tx+, Tx- RS485: Data+, Data- Modem controls: DTR ... /DSR, DCD and RTS/CTS 1-port RS-232/422/485 ...